Balanced putting trainer device

ABSTRACT

A golf club has a shaft with a proximal end and a distal end. A golf club head is attached to the distal end of the shaft. The head has a leading ball-striking face, and a trailing edge with a striking axis defined generally perpendicular to the striking face and a transverse axis defined generally parallel to the striking face. The head includes a polymer insert having a transversely extending face portion and a generally cylindrical portion extending rearwardly therefrom along the striking axis. The face portion has a transverse width greater than the generally cylindrical portion. A metal shell has a body portion surrounding the cylindrical portion and a perimeter ridge extending around the perimeter of the face portion of the polymer insert such that the perimeter ridge of the metal shell and a face portion of the polymer insert cooperate to define the ball-striking face of the golf club head.

REFERENCE TO RELATED APPLICATION

[0001] This application is a continuation-in-part of U.S. patent application Ser. No. 09/483,804, filed Jan. 15, 2000, the entire contents of which is incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates generally to golf training devices and, in particular, to an economical, balanced putter training device that promotes a “perpendicular swing” and/or has an improved sweet spot.

BACKGROUND OF THE INVENTION

[0003] A wide variety of training devices are available to the golf enthusiast. With specific regard to putting, many experts now agree that the ideal stroke is a “pendulum” swing initiated at the shoulders with the wrists locked about the handle of the club. Many the training devices accordingly operate to enforce this pendulum movement. For example, U.S. Pat. No. 3,963,244 discloses a specialized putter consisting of two shafts in spaced-apart parallel relation and pivotally attached, one having a lower ground-engaging member and the other having a putter head, enabling the user to hold one shaft steady while pivoting the other in a pendulum motion. This is not a training device, however, but rather, a specialized putter which operates at 90 degrees relative to conventional clubs, that is, the stroke is forward and away from the golfer as opposed to being from side to side.

[0004] More recent putter training and practice devices include U.S. Pat. No. 4,880,240, which provides a specially constructed putter and a stroke guide worn at the user's waist wherein a pivot point is created, rather than at the shoulders. U.S. Pat. No. 5,308,071 includes an extension attachable to the putter grip and a guide attachable to the waist of a golfer having a narrow horizontal slot to receive a tab on the extension. In one embodiment, the pivot point for pendulum action may be moved up from the waist to the chest area. U.S. Pat. Nos. 5,156,401 and 5,328,185 also teach elongated putters which extend roughly from the chest area down to the golf club head. In U.S. Pat. No. 5,156,401, the upper end includes a cross piece which abuts the user's chest and has end portions which extend under the user's arms to promote and maintain good stance by maintaining a constant triangular shape defined by the user's shoulders and hands. In U.S. Pat. No. 5,328,185, one hand is used to grip the upper end of an elongated putter in the shaft area, while the other hand grips the club midway, using either a small protruding extension or a U-shaped handle. U.S. Pat. No. 5,342,055 includes an elongated rod having a neck-engaging mender and a quick release connector for attaching the rod to the head of the putter. The length of the rod is adjustable and defines the radius of the arc of motion of the club relative to the golfer so that the swing is constrained in a precisely defined path to teach the golfer a repetitive stroke.

[0005] All of the devices just described present certain drawbacks, however, either concerning the manner in which they are used, or in terms of their manufacture. For example, the “pit putter” disclosed in FIGS. 1 and 2 of my U.S. Pat. No. 5,520,392, is typically constructed in the same manner as a conventional putter, though it is much longer to fit under the armpit of a user to promote the desirable pendulum swing. However, in simply extending the length of the golf club shaft, sufficient attention may not be made to weight distribution, resulting in a device which is unbalanced and less effective for training purposes. Since a device of this kind is very useful for putting training, the need remains for an improved, more balanced version of such apparatus, preferably one wherein manufacturing steps may be integrated to reduce costs to the consumer.

[0006] There have also been numerous attempts to expand or improve the “sweet spot” on the head of a golf putter. The sweet spot may be generally defined as the area on the club face that when used to strike a golf ball results in the longest putting distance for a given strength or speed of swing. By expanding and/or improving the sweet spot, putting results may be improved. U.S. Pat. Nos. 6,302,807 to Rohrer; U.S. Pat. No. 5,575,472 to Magerman et al.; and U.S. Pat. No. 4,422,638 to Tucker, all of which are incorporated in their entirety herein by reference, each disclose a golf club head that is at least partially formed with an elastomeric portion so as to affect the sweet spot or striking characteristics of the club. For example, the Rohrer patent specifies a variable energy absorbing means incorporated such that maximum energy is absorbed when a golf ball is struck on the intended strike point and progressively less energy is absorbed as the ball is struck on the striking face at distances incrementally remote from the intended strike point along the horizontal axis. While this approach may help to equalize putting distances from miss-hit putts, it does little to enlarge the actual sweet spot. Instead, the design attempts to equalize putting distances whether the sweet spot is used not. The Tucker patent states that a golf ball typically has a hardness in the range of, or above, 99 Durometer A and 50 Durometer D at the surface of the ball and that traditionally elastomers were chosen with a hardness greater than the hardness of a golf ball. In Tucker, elastomers are specified with a resiliency above about 45 percent rebound and a minimum hardness of about 70 Durometer A and preferably a hardness below the hardness of a golf ball. Despite these attempts, there remains a need for golf clubs with an improved or expanded sweet spot.

SUMMARY OF THE INVENTION

[0007] The subject invention improves upon prior-art putter training devices by providing a fully balanced unit manufactured utilizing integrated fabrication steps to reduce costs. The device features an elongated shaft having an extent long enough that the proximal end may fit under the armpit of a user while the distal end, includes a conventional putter head, may be used to strike a ball as part of a pendulum swing. The device includes two grips, one central to the shaft, preferably including a square shape that locks the wrists, and a second grip covering the proximal end so that it is more comfortable to the user during application.

[0008] In terms of fabrication, the shaft is preferably molded around a rigid element. For example, the shaft may be a thermoset, polymeric material, and the rigid element a metal rod or wire. The grip is molded around the shaft, preferably using the same mold to form the shaft around the rigid element. In the preferred embodiment, a weight is also provided central to the shaft so as to counter-balance the weight of the putter head, such that, with the shaft and grip material formed therearound, the resulting device is balanced not only in terms of swing, but in terms of center of gravity. In some embodiments, this results in adding the weight of approximately 400 grams centered on a position about 21 inches from the sole of the putter. Use of such weight may be applied to a long pit putter, a mid putter designed to have the upper end placed against the belly of the golfer, or a standard putter.

[0009] Standard putters (of 31, 32, 33, 34 and 35 inches in length), as well as mid-putters (designed to have the upper end placed against the golfer's stomach), may be made in the same mold die as a longer pit putter. All are preferably face-balanced, shaft-balanced and counter-balanced, making the manufacturing process very cost-effective. Locking the long putter in a user's armpit locks the wrists so that the hands work together. The long putter allows hands, arms and shoulders to work together as a triangle, promoting a perfect pendulum “lock-and-roll” stroke.

[0010] In further embodiments of the present invention, a club head with an improved sweet spot is provided. The club head has a leading ball striking face and a trailing edge with a striking axis defined generally perpendicular to the striking face and a transverse axis defined generally parallel to the striking face. The golf club head has a polymer insert with a transversely extending face portion and a generally cylindrical portion extending rearwardly therefrom along the striking axis. The face portion has a transverse width greater than the generally cylindrical portion. The metal shell has a body portion surrounding the cylindrical portion of the polymer insert and a perimeter ridge extending around the perimeter of the face portion of the polymer insert such that the perimeter ridge of the metal shell and the face portion of the polymer insert cooperate to define the ball striking face of the golf club head. The polymer insert defines the majority of the ball striking face so as to alter the feel of the club. In addition, the cylindrical portion that extends from behind the ball striking face creates a large sweet spot for improved putting.

BRIEF DESCRIPTION OF THE DRAWING

[0011]FIG. 1 illustrates, from an oblique perspective, a preferred embodiment of a long putter according to the present invention;

[0012]FIG. 2 is a perspective view of an improved golf club head according to one aspect of the present invention;

[0013]FIG. 3 is a perspective view of the golf club head of FIG. 2 showing the trailing edge with the polymer insert extending to the trailing edge;

[0014]FIG. 4 is a generally horizontal cross-sectional view of the golf club head of FIGS. 2 and 3 showing the cross-sectional shape of the polymer insert; and

[0015]FIG. 5 is a generally vertical cross-section taken along lines 5-5 of FIG. 4.

DETAILED DESCRIPTION OF THE INVENTION

[0016] A preferred embodiment of the invention is depicted generally at 100 in FIG. 1. The device includes an elongated shaft 102 having a distal end with a putter head 104 that is heel-, toe- and face-balanced. For example, a curved section 106 may be provided as is often the case with conventional putters. The shaft 102 is sufficiently long that the proximal end fits under the armpit of a user, thereby encouraging a pendulum-type swing, as shown in FIGS. 1 and 2 of my U.S. Pat. No. 5,520,392.

[0017] Central along the shaft 102, there is disposed a first soft grip 108. The shaft continues to a section 110 which is preferably smooth and circular in cross-section, before encountering a second soft grip 112 to ease comfort to the user during use. Although square grip shapes are shown, round or contoured grips may be used.

[0018] The device described herein may be manufactured in a number of ways though, in the preferred embodiment, an integral molding process is used to save on costs. As part of this process, a mold is produced having a cavity which conforms to the desired outer dimensions of the device overall. A face insert 120 is placed into the mold of the putter head 104, as well as a weight in the central section 130 of the shaft area (not visible in the figure), and the weight and insert are connected to one another with a rigid form such as a metal rod. These internal weights and rigid components are sized to be somewhat less than the outer dimensions of the device overall, so that when mold material such as a thermoset polymer plastic is introduced into the mold, these internal components are completely covered.

[0019] To further save on manufacturing costs, the same mold is preferably used to form the grip portions of the device. In particular, inserts are used in the mold with respect to the first injection of the thermoplastic material, which forms a hard surface around the shaft. However, inserts are placed in the mold in the areas forming grips 108 and 112, and, prior to the first material completely setting, these inserts are completely removed. A second injection of softer material is then introduced into the voids caused by the removal of the inserts, thereby forming the grips 108 and 112, as shown in the figure. Particularly if the harder material has not yet set, the grip portions will adhere to form a strong permanent bond to the device.

[0020] According to the present invention, weight may be added to the shaft of the club 100 as described above, or may be added in any other way. Typically, a standard length putter shaft weighs 80-100 grams, while the longer shaft 102, without additional weights, has a weight between 100-200 grams. Referring again to FIG. 1, the putter may be said to have a sole or lower surface 132, which defines the lowermost point of the putter 100 in the putting position. According to one embodiment, a weight of approximately 400 grams is added centered on a position approximately 21 inches from the lower surface 132 of the club 100. The weight may be very dense and located specifically on the position, or may be more spread out such that a portion of the weight is above and below the center of weight. In one embodiment, the weight is spread out over a distance of about 4 inches up and down the shaft. Lead weights may be embedded in the shaft, or other means of achieving the additional weight may be used. As will be clear to those of skill in the art, the position of the weight may be adjusted upwardly or downwardly somewhat, depending on the application. For example, in some embodiments the center point of the weight may be in a position ranging between 19 and 23 inches from the lower surface. In yet other embodiments, the weight may have a center point position between 17 and 25 inches from the lower surface. Also, more or less weight may be used depending on the application. For example, in some embodiments, the weight may range between 380-420 grams. In further embodiments, the weight may vary between 350-450 grams. In yet further embodiments, the weight may range between 300-500 grams. Also, weights in the ranges and positions described may be used in other lengths of putters. For example, weights may be provided in a standard putter, having an overall length of 31-35 inches. Also, weights may be provided in a mid-length putters, known as a mid-putter or belly anchor putter. A mid-putter has an overall length designed to allow the golfer to place the proximal end against their stomach and to pivot the stomach along with the upper body to swing the club. Once again, weights in the ranges and positions described may be placed in a mid-putter, or a standard length putter.

[0021] Referring now to FIGS. 2 and 3, a preferred golf club head for a putter will be described. This head design may be used with a standard length putter, a mid putter, or a long putter, such as shown in FIG. 1. Also, the head design may be used with the weights as previously described. The golf club head 200 is connected to a shaft 202, which may be of various lengths. The illustrated golf club head 200 is of the type described as a mallet style head with a generally puck-shaped body 204 that is truncated at the leading edge to provide a ball-striking face 206. The body 204 may be said to extend from the leading ball-striking face 206 to a trailing edge 218 and have an upper surface 208 and a lower surface 210. According to the present invention, the body 204 is composed primarily of a metal, such as aluminum with a polymer insert defining a portion of the ball-striking face 206 and extending through the body. The club head 200 may be said to have a striking axis A extending from the ball striking face 206 to the trailing edge 218. The striking axis is generally aligned with the axis of movement of the golf club head at the moment of ball striking and may be said to extend generally perpendicularly to ball striking face 206. A transverse axis B may be defined as generally perpendicular to the striking axis A and parallel to the face 206. As illustrated, the ball striking face 206 may be said to have a perimeter portion 212 formed of the metal material and a central portion 214 formed of a polymer material. As shown, the polymer central portion 214 has a perimeter shape similar to the perimeter shape of the entire striking face 206, such that the perimeter portion 212 is generally narrow, and may have a generally constant width. Therefore, the polymer portion 214 defines a majority of the ball striking face, and in some embodiments may define the entire face. The polymer portion 214 of the face 206 is preferably generally planar with a generally constant thickness of ⅛ of an inch or more. Described in another way, the metal portion of the club head 200 may be said to have a perimeter ridge 212 defining a portion of the face 216 with a central recessed area that is filled by the polymer portion 214.

[0022] In one embodiment, the mallet style putter head has a transversed width of approximately 4 ¼ inch, a height of approximately 1 inch, and a length (from striking face 206 to the trailing edge 218) of approximately 2 ⅜ inch. However, the present invention may be used with putter heads of other shapes, sizes, and styles. The polymer portion 214 may be any of several various materials, including plastics, composites, and rubber materials, as well as other materials differing from the metal portion of the body 204. In some embodiments, the polymer has a hardness less than a typical golf ball, while in other embodiments the hardness is greater than a typical golf ball. The polymers used for the polymer insert may be of various levels of elasticity and energy absorption. For example, in some embodiments, highly elastic and/or highly energy absorbing polymer may be used, while in other embodiments a more inelastic and/or less energy absorbing polymer may be used.

[0023] As best shown in FIGS. 3, 4 and 5, a cylindrical bore 215 is defined from the ball striking face 206 to the trailing edge 218 through the metal body 204. This generally cylindrical bore 215 is filled with a polymer 216. The polymer 216 is preferably the same as the polymer 214, though differing materials may be used. As best shown in FIG. 4, the polymer face portion 214 has a significantly greater transverse width than the cylindrical portion 216, thereby giving the polymer portion of the golf club head a generally T-shaped horizontal cross-section. In some embodiments, the bore 215 is approximately ¾ of an inch in diameter. In other embodiments, the bore may be larger or smaller, or may taper. Also, the bore may be of different shapes, including having an octagonal or square vertical cross-sectional shape. The transition between the polymer face portion 214 and the cylindrical portion 216 is shown as a square corner. However, this transition may be beveled or radiused.

[0024] The golf club head 200 may be manufactured by first forming an aluminum body. The recess of the front face may then be machined and a bore drilled along the striking axis. The recess and bore may then be filled with a polymer material. Preferably, the striking face 206 is then remachined to create a generally flat face. The polymer insert 214 and the aluminum perimeter 212 cooperate to form the striking face 206. As shown in FIGS. 2 and 3, the upper surface 208 of the golf club head 200 preferably has dual alignment grooves 220 extending generally parallel to the striking axis. The alignment grooves 220 preferably are spaced apart by a distance equal to the diameter of the golf ball. This helps a golfer to align the golf ball with the sweet spot of the club head 200.

[0025] Preferably, the mallet-style golf club head 200 is heavier front-to-back than other designs, thereby allowing for a more controlled putting stroke. This assists in creating a properly counter-balanced putter. The mallet-style head is also preferably face-balanced. A face-balanced putter may be described as one having the weight equally distributed, heel to toe, about the longitudinal axis of the golf club shaft or the axis of rotation of the golf club shaft. The club head may also be heel-toe balanced, as described in U.S. Pat. No. 5,961,400, which is incorporated herein in its entirety by reference. The wide sole of the mallet-style club head contributes to a stable, consistent stroke while the head's extra mass offers a firm and confident feel. Preferably, the mallet-style putter head has most of the head weight located behind the ball-striking area. In embodiments including shaft weights, as previously described, this weighting of the putter head in combination with the weight in the shaft contributes to the putter being “triple-balanced.” That is, the putter is face-balanced, shaft-balanced (as caused by the weight in the shaft), and counterweight-balanced by the weight in the head close to the ground to promote a pure pendulum stroke. Testing using a testing robot has validated these affects. The T-shaped polymer insert with its larger sweet spot preferably creates more dwell time (contact time between golf ball and striking face), thereby helping to eliminate the skid and bounce of the ball after impact. Robot testing also indicated a ¼ inch in deviation from the sweet spot resulted only in a minimal loss of distance.

[0026] While the present specification and drawings are directed to preferred embodiments of the present invention, those of skill in the art will appreciate that alterations may be made without departing from the scope of the present invention. It is following claims, including all equivalents, which define the scope of the present invention. 

I claim:
 1. A golf club comprising: a shaft having a proximal end and a distal end; a club head attached to the distal end of the shaft having a leading ball striking face and a trailing edge, the ball striking face having a perimeter shape, a width and a height associated therewith, a striking axis being defined from the ball striking face to the trailing edge and a transverse axis defined perpendicular to the striking axis, the club head comprising: a metal portion having a forward face and a trailing edge, the forward face having a perimeter ridge defining the perimeter of the striking face and a recessed central area, a generally cylindrical bore being defined from the forward face to the trailing edge, the bore being generally aligned with the striking axis; and a polymer insert having a generally cylindrical portion filling the bore in the metal portion and a face portion filling the recessed central portion of the metal portion and defining the remainder of the striking face, the face portion having a perimeter shape generally similar to the perimeter shape of the ball striking face such that the perimeter ridge has a generally constant width, the face portion having a transverse width greater than the cylindrical portion such that the polymer insert has a generally T-shaped horizontal cross section.
 2. The golf club of claim 1, wherein the face portion has a generally constant thickness.
 3. The golf club of claim 1, wherein the face portion has a thickness of approximately {fraction (1/8)} inch.
 4. The golf club of claim 1, wherein the polymer is a viscoelastic material.
 5. The golf club of claim 1, wherein the polymer has a hardness greater than the hardness of golf ball.
 6. The golf club of claim 1, wherein the polymer has a hardness less than the hardness of a golf ball.
 7. The golf club of claim 1, wherein the metal portion is aluminum.
 8. The golf club of claim 1, wherein the head has an upper surface with a pair of visible parallel lines disposed thereon, the lines being generally parallel to the striking axis and spaced apart by the width of a golf ball.
 9. The golf club of claim 1, wherein the club is face balanced.
 10. The golf club of claim 1, wherein the club head has a lower surface and the shaft has weight of 300 to 500 grams added centered on a distance between 17 and 25 inches from the lower surface of the club head.
 11. The golf club of claim 1, wherein the head is a mallet style putter head.
 12. A golf club comprising: a shaft having a proximal end and a distal end; a golf club head attached to the distal end of the shaft, the golf club head having a leading ball striking face and a trailing edge with a striking axis defined generally perpendicular to the striking face and a transverse axis defined generally parallel to the striking face, the head comprising: a polymer insert having a transversely extending face portion and a generally cylindrical portion extending rearwardly therefrom along the striking axis, the face portion having a transverse width greater than the generally cylindrical portion; and a metal shell having a body portion surrounding the cylindrical portion and a perimeter ridge extending around the perimeter of the face portion of the polymer insert such that the perimeter ridge of the metal shell and the face portion of the polymer insert cooperate to define the ball striking face of the golf club head.
 13. A golf club comprising: a shaft having a proximal end and a distal end; and a golf club head attached to the distal end of the shaft, the golf club head comprising: a body having a generally planar ball striking face and an opposed trailing edge interconnected by upper and lower surface extending therebetween, the ball striking face having a metal perimeter and a polymer central portion; and a generally cylindrical polymer central core extending from the polymer central portion of the ball striking face to the trailing edge of the body. 